Systems and methods for virtual ignition detection

ABSTRACT

Systems and methods for determining vehicle ignition state using a device added to the vehicle after the manufacture of the vehicle without a direct connection to the vehicle ignition line are disclosed. In a number of embodiments, a system includes a processor, a motion detector configured to detect vehicle motion and to enable the processor to obtain motion data, a Global Positioning System (GPS) receiver configured to determine location and to enable the processor to obtain at least speed data, and a radio transceiver configured to communicate with the processor. Additionally, the processor is configured to estimate the ignition state of a vehicle using at least the motion data and the speed data.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional. Application No.61/256,989 filed Oct. 31, 3009 and U.S. Provisional. Application No.61/257,137 filed Nov. 2, 2009, the disclosures of which are incorporatedherein by reference.

FIELD OF THE INVENTION

The present invention relates generally to vehicle telematics systemsand more specifically to the detection of vehicle ignition by a vehicletelematics system.

BACKGROUND

A vehicle telematics system is typically a system installed in a vehiclethat is capable of determining the location of the vehicle andcommunicating the vehicle's location to a remote location via a wirelesscommunication link. Vehicle telematics systems are installed in avariety of applications including, but not limited to, fleet management,vehicle finance, vehicle maintenance, driver management, and/or fuelmanagement.

A common configuration for a vehicle telematics system is illustrated inFIG. 1. The vehicle telematics system 10 includes a processor 12 that isconfigured to communicate with a radio transceiver 13 and a GPS receiver14. The processor 12, the radio transceiver 13, and the GPS receiver 14are typically powered by a power supply 15 that is connected via a lineto the vehicle's battery. The vehicle telematics system can optionallyinclude its own battery 16 to enable operation when the vehicle batteryis removed and/or to prevent depletion of the vehicle battery. In manyinstances, the vehicle telematics system monitors the ignition line ofthe vehicle to determine the ignition state of the vehicle using anignition input interface 17 that is connected to the vehicle ignitionline. Monitoring the vehicle ignition state can be useful for reasonsincluding, but not limited to, reporting vehicle ignition state and/ormanaging power consumption.

A common problem encountered during installation of devices in a motorvehicle that connect to the vehicle's electrical system is that theinstaller may inadvertently connect the ignition input interface 17 to awire that is not the vehicle ignition line. U.S. Pat. No. 6,163,690, thedisclosure of which is incorporated by reference herein in its entirety,notes the potential for the ignition sense line of a hands-free adapterfor a mobile phone to be incorrectly connected to a line other than theignition line due to installer error, which can result in the hands-freeadaptor believing the ignition is always on and undesirably draining thevehicle's battery. U.S. Pat. No. 6,163,690 proposes a system that checksthe correctness of the ignition sense line installation by monitoringthe ignition sense line to determine whether the ignition line isswitched off within a predetermined time period. In the event that thehands-free adaptor detects that the ignition line is always on, thehands-free adaptor provides an indication that it has been installedincorrectly.

SUMMARY OF THE INVENTION

Systems and methods are described for estimating the ignition state of avehicle without connecting to the vehicle's ignition line. In a numberof embodiments, vehicle telematics systems that do not include directconnections to the vehicle ignition line are configured to determinevehicle ignition state. In several embodiments, aspects of the powersupply are monitored to determine the vehicle ignition state, includingbut not limited to, changes in the voltage on the power supply line, thenoise level on the power supply line, and/or the AC coupling on the DCpower supply line. In many embodiments, vehicle vibration indicative ofignition status is detected using an accelerometer. In a number ofembodiments, rate of voltage transitions (i.e., message frequency) onthe OBD or other data bus line is monitored to observe activityindicative of vehicle ignition. Voltage averaging may also be used toobserve activity indicative of vehicle ignition. This may includevoltage averaging on the OBD or other data bus line monitored to observeactivity indicative of vehicle ignition. In many instances, techniquesincluding those outlined above are used in combination with GPS data todetermine vehicle ignition status. By eliminating the need to connect toa vehicle ignition line, systems and methods in accordance withembodiments of the invention simplify the installation process andreduce the likelihood that errors in the installation process willnegatively impact the performance of the installed device.

In a number of embodiments, a system includes a processor, a motiondetector configured to detect vehicle motion and to enable the processorto obtain motion data, a Global. Positioning System (GPS) receiverconfigured to determine location and to enable the processor to obtainat least speed data, and a radio transceiver configured to communicatewith the processor. Additionally, the processor is configured toestimate the ignition state of a vehicle using at least the motion dataand the speed data.

In a further embodiment, the motion detector is an accelerometer.

In another embodiment, the processor is configured to activate the GPSreceiver upon detection of vehicle motion.

In an additional embodiment, the speed data is derived using the DopplerEffect.

In a still further embodiment, the speed data is derived usingdifferences in location over time.

In a still other embodiment, the processor is configured to start atimer when the motion data and the position data are below predeterminedthresholds, and the processor is configured to place the GPS receiver ina sleep mode when the motion data and the speed data remain below thepredetermined thresholds for the duration of the timer.

In a still additional embodiment, the processor is further configured tomatch the motion data against specific signatures indicative of avehicle being towed.

In a yet further embodiment includes a power supply configured toconnect to a power line and a voltage detector configured to enable theprocessor to obtain voltage data. Additionally, the voltage data isindicative of voltage measurements at the power supply.

A yet other embodiment includes a power supply configured to connect toa power line and a noise detector configured to enable the processor toobtain noise data. Additionally, the noise data is indicative of arunning engine.

A yet additional embodiment includes a vehicle bus detector configuredto enable the processor to obtain bus data, wherein the bus data isindicative of voltage transitions on a vehicle data bus.

A number of embodiments include detecting vehicle motion using a motiondetector, detecting vehicle speed using a Global. Positioning System(GPS) receiver, estimating the ignition state of a vehicle using aprocessor using at least the detected vehicle speed and vehicle motionand transmitting the ignition state estimated by the processor to aremote device using a radio transceiver.

In a further embodiment, the detecting vehicle motion further comprisesusing an accelerometer as a motion detector.

Another embodiment includes detecting vehicle speed in response todetection of vehicle motion.

In an additional embodiment, the speed data is derived using the Dopplereffect.

In a still further embodiment, the speed data is derived usingdifferences in location over time.

A still other embodiment includes starting a timer after detection ofmotion when the detected vehicle motion and vehicle speed are belowpredetermined thresholds and sleeping the GPS receiver when the vehiclemotion and vehicle speed remain below the predetermined thresholds forthe duration of the timer.

A still additional embodiment includes detecting towing of the vehicleby matching the detected motion against specific signatures indicativeof a vehicle being towed using the processor.

A yet further embodiment includes detecting voltage using a voltagedetector. Additionally, the voltage is indicative of voltagemeasurements at a power supply configured to connect to a power line.Also, the processor utilizes the detected voltage when estimating theignition state of a vehicle.

A yet other embodiment includes detecting noise using a noise detector.Additionally, the noise is indicative of a running engine. Also, theprocessor utilizes the detected noise when estimating the ignition stateof a vehicle.

A yet additional embodiment includes detecting voltage transitions usinga vehicle data bus. Additionally, the voltage transitions are indicativeof voltage transitions on a vehicle data bus. Also, the processorutilizes the detected voltage transitions when estimating the ignitionstate of a vehicle.

Numerous embodiments include a processor configured to estimate theignition state of a vehicle, a motion detector configured to detectvehicle motion and to enable the processor to obtain motion data.Additionally, the motion detector is an accelerometer.

Numerous embodiments provide a Global. Positioning System (GPS) receiverconfigured to determine location and to enable the processor to obtainat least speed data. Additionally, the speed data is derived usingdifferences in location over time. Also, the processor is configured toactivate the GPS receiver upon detection of vehicle motion. Furthermore,the processor is configured to start a timer when the motion data andthe position data are below predetermined thresholds. Moreover, theprocessor is configured to place the GPS receiver in a sleep mode whenthe motion data and the speed data remain below the predeterminedthresholds for the duration of the timer.

Numerous embodiments provide a radio transceiver configured tocommunicate with the processor.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a block diagram of a prior art vehicle telematics system.

FIG. 2 is a block diagram showing a variety of device configurations inwhich the device can determine vehicle ignition state without a directconnection to the vehicle ignition line in accordance with an embodimentof the invention.

FIGS. 2A and 2B are charts conceptually illustrating vehicle batteryvoltage when a vehicle's ignition state goes from OFF to ON and from ONto OFF.

FIG. 3 is a flow chart illustrating a process for determining vehicleignition state based upon the output of a motion detector and a GPSreceiver in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Turning now to the drawings, systems and methods for determining vehicleignition state using a device added to the vehicle after the manufactureof the vehicle without a direct connection to the vehicle ignition lineare illustrated. In many instances, the device is installed in alocation where the vehicle ignition line is available to the devicehowever the device does not utilize a connection to the vehicle ignitionline to simplify installation. In a number of embodiments, vehicleignition state is ascertained by monitoring the vehicle for signsindicative of the vehicle ignition state without directly connecting tothe vehicle ignition line. Information indicative of vehicle ignitionstate can be ascertained by observing characteristics of the vehicleincluding but not limited to the power supplied by the vehicle, vehiclevibration, communications on an OBD or other data bus line, and/orvehicle position information. In many embodiments, multiple differenttypes of information are combined to ascertain the vehicle ignitionstate. Although much of the following discussion references vehicletelematics systems, systems and methods in accordance with embodimentsof the invention can be implemented in other devices installed aftervehicle manufacture that connect to a vehicle power supply.

Devices Configured to Detect Vehicle Ignition State

A device configured to determine vehicle ignition state without a directconnection to the vehicle ignition line is illustrated in FIG. 2. In itssimplest configuration, the device 20 includes a processor 22, and apower supply 24 that is connected to the vehicle power source. A batterycan be optionally provided 25 to provide an alternative source of powerto the power supply. When the device is a vehicle telematics system, thedevice 20 also includes a radio transceiver 26 and a GPS receiver 28.The processor can obtain position information via the GPS receiver 28and communicate information, including but not limited to positioninformation, with external devices over a wireless communication linkusing the radio transceiver 26. In a number of embodiments, the wirelesstransceiver is configured to communicate via a mobile or cell phonenetwork. The device illustrated in FIG. 2 is not configured to directlyconnect to a vehicle ignition line. Instead, the device can estimate thevehicle ignition state using one of a variety of techniques inaccordance with embodiments of the invention. Although a specific deviceconfiguration is shown in FIG. 2, devices in accordance with embodimentsof the invention can include any of a variety of configurationsincluding configurations in which the GPS receiver includes a processorthat also acts as the processor 22 shown in FIG. 2. Various techniquesfor determining vehicle ignition state in accordance with embodiments ofthe invention are discussed below.

Ignition Sensing Using Motion Detection

Devices, such as vehicle telematics systems, in accordance withembodiments of the invention can include a motion detector 30 and a GPSreceiver 28. A detector may be combined with a part of a system, such asthe processor, or may be a separate device. A detector also includes anydevices and/or interfaces that may relate to an area of interest, suchas motion. In a number of embodiments, the motion detector 30 possessesthe ability to determine acceleration. Examples of motion detectorsinclude but are not limited to MEMS based accelerometers. The motiondetector can be used to detect vibration and other motions of thevehicle. After a period in which the motion detector has not detectedmotion, the sudden detection of motion is typically indicative of thevehicle ignition being activated. Once activated, the absence of motionfor a predetermined period of time can be indicative of the vehiclestate being OFF. In many instances, the measurements of the motiondetector can be supplemented by the output of a GPS receiver. However,the GPS receiver is often put into a sleep mode, such as a power savingmode where the GPS receiver may operate on power ranging from less thanfull power. For example in operations including a sleep or power savingmode, the GPS antenna may be powered down to a level in which allmodules of the GPS receiver are powered down except the nnodule(s) thatmanage waking of the GPS receiver during periods in which the vehicle isnot running (i.e. ignition state is OFF). Therefore, the motion detectoralone is relied upon to make an initial determination that the vehicleis in motion when the GPS receiver is in sleep mode.

A process for estimating vehicle ignition state using a motion detectorand a GPS receiver is illustrated in FIG. 3. The process 50 involvesdetecting (52) motion. When motion is detected, the process assumes thata transition from ignition state OFF to ignition state ON has occurred.The GPS receiver is woken (54) from a sleep or power save mode, and aGPS fix is acquired (56). As long as the motion detector continues todetect motion or the vehicle speed measured by the GPS receiver exceedsa predetermined value (in the illustrated embodiment 3 mph), the processcontinues detecting (58) motion and determining speed as necessary.Speed data may be a directly determined speed or velocity value (e.g.calculated based upon the Doppler effect observed in the signalsreceived by the GPS receivers), multiple time stamped positionmeasurements that can be used to calculate speed (e.g. differences inlocation over time), or other data indicating speed. In the event thatthe motion detector does not detect motion and the vehicle speed isbelow the predetermined threshold, a timer is started (60). The processcontinues detecting (62) motion and determining speed and determining(64) whether motion is absent and the vehicle speed is remaining belowthe predetermined threshold. In the event that motion is detected, thetimer is cleared (66). In the event that the state of no motion andspeed below a predetermined threshold persists until the timer expires(68), then the process assumes that the ignition state is OFF, places(70) the GPS receiver in sleep mode, and returns to monitoring (52) themotion of the vehicle to detect the ignition state returning to ON.

Although a specific process is illustrated in FIG. 3, in otherembodiments the output of the motion detector is analyzed with moreprecision. For example, the output of the motion detector could bematched against specific signatures indicative of vehicle ignition orindicative of the vehicle being towed. Furthermore, the output of themotion detector can be the sole basis of determining the ignition stateof the vehicle, or the output of the motion detector can be consideredin combination with additional information that may or may not include aGPS receiver. Accordingly, embodiments of the invention can utilizeinformation generated by a motion detector in any of a variety of waysto estimate vehicle ignition state.

Ignition Sensing Using Input Voltage Measurement

Referring back to FIG. 2, devices in accordance with a number ofembodiments of the invention can incorporate an input voltagemeasurement interface 32 that is connected to the power line connectedto the power supply. The input voltage measurement interface includescircuitry that measures voltage levels on the power line andcommunicates the power level to the device's processor 22.

A chart conceptually illustrating vehicle battery voltage when avehicle's ignition state goes from OFF to ON is illustrated in FIG. 2A.At startup (transitions due to starter motor load are not shown), thevoltage will immediately increase from the initial battery voltage 41 tothe voltage output by the regulator of the vehicle alternator 42. Thebattery can initially be at a voltage ranging from heavily discharged toa voltage close to that of the alternator (especially when the vehiclewas recently shut off and surface charge has not yet dissipated). Achart conceptually illustrating vehicle battery voltage when a vehicle'signition state goes from OFF to ON is illustrated in FIG. 2B. When theignition state goes from ON to OFF, the voltage typically starts to dropfrom the alternator voltage 43 toward the nominal battery voltage. Therate of the discharge can take anywhere from a few seconds up to severalhours, depending on many factors including the condition of the batteryand any remaining load on the battery. The input voltage measurementinterface or the processor can look for increases or decreases involtage level indicative of the ignition state transitioning from OFF toON or ON to OFF. In addition, the processor can combine informationcollected through the input voltage measurement interface in combinationwith other information including but not limited to informationcollected via a motion detector and/or a GPS receiver.

Ignition Sensing Using Noise Detection

Devices in accordance with many embodiments of the invention canincorporate a noise detector interface. A noise detector interface 34 issimilar to an input voltage measurement interface with the exceptionthat the noise detector interface looks at whether noise is indicativeof a running engine or an operating vehicle or other noise that may givesignals indicative of vehicle ignition state, which in some cases may bethe high frequency components of the voltage on the power line. U.S.Pat. No. 5,903,063, the disclosure of which is incorporated herein byreference in its entirety, proposes a circuit for use in vehicleelectronics systems that provides power to components of the vehicle'selectrical system when noise on the vehicle power line, which isindicative of vehicle ignition, exceeds predetermined criteria. Thecircuit described in U.S. Pat. No. 5,903,603 is intended to reduce theneed for automobile manufacturers to install ignition conductorsthroughout the vehicle. The observation in U.S. Pat. No. 5,903,063 thathigh frequency noise above a predetermined threshold on the power lineis indicative of an ignition state of ON can also be relied upon bydevices installed in the vehicle after manufacture. Devices inaccordance with embodiments of the invention use the detected noise torecord information concerning the vehicle's ignition status. Therefore,the noise detector interface includes circuitry to detect when the highfrequency noise exceeds a predetermined threshold and to provide theinformation to the processor 22. The processor can utilize theinformation either alone or in combination with information from othersources, such as the output of a motion detector, to determine that theignition state has transitioned from OFF to ON or vice versa. Thedetermination can be the basis of waking devices such as GPS receiversthat consume additional power, and that can provide additionalinformation concerning the state of the vehicle. The determination canalso be the basis of logging information concerning the vehicle'sjourney, such as the time at which the journey commenced, and forinterpreting information from a GPS receiver, such as understanding thata stationary vehicle with an ignition state of ON may not have completedits journey. Accordingly, a variety of circuits can be utilized toimplement a noise detector interface in accordance with an embodiment ofthe invention and to provide information to the processor to be used inthe estimation of the vehicle ignition state.

Ignition Sensing by Observing the Vehicle Bus

Devices in accordance with embodiments of the invention can include avehicle bus detector or interface 36 that connects to a vehicle databus, such as an OBD-II bus, via a vehicle data bus connection 38. If thedevice does not otherwise need to communicate via the vehicle data bus,then there is very little benefit to implementing all of thefunctionality required to communicate via the bus. However, a simplercircuit can be used to measure the rate of voltage transitions on thevehicle bus and using the rate as an indicator of the vehicle ignitionstate. In a simple implementation, the system can provide the rate or anindication of whether the rate exceeds a predetermined threshold to theprocessor 22. In more advanced implementations, the processor could lookfor patterns indicative of specific events such as vehicle ignition orthe vehicle ignition being turned OFF. In still more implementations,voltage averaging may also be used to observe activity indicative ofvehicle ignition. This may include voltage averaging on the OBD or otherdata bus line monitored to observe activity indicative of vehicleignition. Accordingly, a variety of techniques can be used in accordancewith embodiments of the invention to determine vehicle ignition statususing observations of signals, instead of data, received via the vehiclebus either alone or in combination with information concerning thevehicle ignition state derived from other sources.

While the above description contains many specific embodiments of theinvention, these should not be construed as limitations on the scope ofthe invention, but rather as an example of one embodiment thereof. Forexample, additional sensors such as audio sensors can be used to obtaininformation indicative of vehicle ignition state. Accordingly, the scopeof the invention should be determined not by the embodimentsillustrated, but by the appended claims and their equivalents.

1. A system configured to estimate the ignition state of a vehiclewithout a connection to the ignition line of the vehicle, comprising: aprocessor; a motion detector configured to detect vehicle motion and toenable the processor to obtain motion data; a Global Positioning System(GPS) receiver configured to determine location and to enable theprocessor to obtain at least speed data; and a radio transceiverconfigured to communicate with the processor; wherein the processor isconfigured to estimate the ignition state of a vehicle using at leastthe motion data and the speed data.
 2. The system of claim 1 wherein themotion detector is an accelerometer.
 3. The system of claim 1 whereinthe processor is configured to activate the GPS receiver upon detectionof vehicle motion.
 4. The system of claim 1 wherein the speed data isderived using the Doppler effect.
 5. The system of claim 1 wherein thespeed data is derived using differences in location over time.
 6. Thesystem of claim 1, wherein: the processor is configured to start a timerwhen the motion data and the position data are below predeterminedthresholds; and the processor is configured to place the GPS receiver ina sleep mode when the motion data and the speed data remain below thepredetermined thresholds for the duration of the timer.
 7. The system ofclaim 1 wherein, the processor is further configured to match the motiondata against specific signatures indicative of a vehicle being towed. 8.The system of claim 1, further comprising: a power supply configured toconnect to a power line; and a voltage detector configured to enable theprocessor to obtain voltage data, wherein the voltage data is indicativeof voltage measurements at the power supply.
 9. The system of claim 1,further comprising: a power supply configured to connect to a powerline; and a noise detector configured to enable the processor to obtainnoise data, wherein the noise data is indicative of a running engine.10. The system of claim 1, further comprising: a vehicle bus detectorconfigured to enable the processor to obtain bus data, wherein the busdata is indicative of voltage transitions on a vehicle data bus.
 11. Amethod for estimating the ignition state of a vehicle without connectingto the vehicle's ignition line, the method comprising: detecting vehiclemotion using a motion detector; detecting vehicle speed using a GlobalPositioning System (GPS) receiver; estimating the ignition state of avehicle using a processor based on at least the detected vehicle speedand vehicle motion; and transmitting the ignition state estimated by theprocessor to a remote device using a radio transceiver.
 12. The methodof claim 11 wherein the detecting vehicle motion further comprises usingan accelerometer as a motion detector.
 13. The method of claim 11further comprising detecting vehicle speed in response to detection ofvehicle motion.
 14. The method of claim 11 wherein the speed data isderived using the Doppler effect.
 15. The method of claim 11 wherein thespeed data is derived using differences in location over time.
 16. Themethod of claim 11, further comprising: starting a timer after detectionof motion when the detected vehicle motion and vehicle speed are belowpredetermined thresholds; and sleeping the GPS receiver when the vehiclemotion and vehicle speed remain below the predetermined thresholds forthe duration of the timer.
 17. The method of claim 11, furthercomprising: detecting towing of the vehicle by matching the detectedmotion against specific signatures indicative of a vehicle being towedusing the processor.
 18. The method of claim 11, further comprising:detecting voltage using a voltage detector, wherein the voltage isindicative of voltage measurements at a power supply configured toconnect to a power line; and wherein the processor utilizes the detectedvoltage when estimating the ignition state of a vehicle.
 19. The methodof claim 11, further comprising: detecting noise using a noise detector,wherein the noise is indicative of a running engine; and wherein theprocessor utilizes the detected noise when estimating the ignition stateof a vehicle.
 20. The method of claim 11, further comprising: detectingvoltage transitions using a vehicle data bus, wherein the voltagetransitions is indicative of voltage transitions on a vehicle data bus;and wherein the processor utilizes the detected voltage transitions whenestimating the ignition state of a vehicle.
 21. A system configured toestimate the ignition state of a vehicle without a connection to theignition line of the vehicle, comprising: a processor configured toestimate the ignition state of a vehicle; a motion detector configuredto detect vehicle motion and to enable the processor to obtain motiondata; wherein the motion detector is an accelerometer; a GlobalPositioning System (GPS) receiver configured to determine location andto enable the processor to obtain at least speed data; wherein the speeddata is derived using differences in location over time. the processoris configured to activate the GPS receiver upon detection of vehiclemotion; the processor is configured to start a timer when the motiondata and the position data are below predetermined thresholds; and theprocessor is configured to place the GPS receiver in a sleep mode whenthe motion data and the speed data remain below the predeterminedthresholds for the duration of the timer; and a radio transceiverconfigured to communicate with the processor.